MK-677 is an orally active growth hormone secretagogue that mimics ghrelin at the GHSR to increase GH and IGF-1. It has been shown to support muscle mass, bone density, sleep quality, and fat loss and is explored for age-related decline, GH deficiency, and muscle wasting.
MK-677 (Ibutamoren)
Also known as: MK-0677; L-163,191; Oratrope
Overview
Benefits
- Muscle growth
- Bone health
- Fat loss
- Anti-aging support
- Better sleep quality
Consider This Peptide If You Want To
- Boost GH for muscle, fat loss, and recovery
- Improve sleep quality and metabolic health
Dosage & Administration
Dosage Guidelines
Recommended Dosage
• Amount:10 mg
• Frequency:weekdays
• Duration:8 weeks
• Rest Period:8 weeks
• Time of Day:morning
• Ingestion:subcutaneous
Administration Routes:Subcutaneous
Research Findings on Dosage:
• Subcutaneous Injection:
◦ Commonly Reported Dosage: 12.5-25 mg, may be divided into 2 doses, (12.5 mg recommended for women)
▪ Month 1: 5 days on, 2 days off
▪ Month 2-3: 3 days per week
◦ Duration: 8-12 week cycles with 8-12 week break
▪ Administration Notes:
• Administer on an empty stomach 30 minutes before eating/2 hours after eating to enhance GH release.
• Fat Burning: administer before workout in a fasted state
• Muscle Building: administer after workout in a fasted state
• Sleep: administer before bed in a fasted state
• Anti-Aging: administer in morning in a fasted state
Mechanism of Action
Mechanism of Action
How this peptide works in the body
GH Secretion:
MK-677 binds to the growth hormone secretagogue receptor (GHSR-1a) in the hypothalamus and pituitary gland, mimicking ghrelin and stimulating adenylate cyclase, which increases cyclic adenosine monophosphate (cAMP) levels. Elevated cAMP activates protein kinase A (PKA), which phosphorylates cAMP response element-binding protein (CREB), enhancing the transcription of growth hormone-releasing hormone (GHRH). This leads to increased growth hormone (GH) and insulin-like growth factor-1 (IGF-1) synthesis, promoting muscle growth, fat metabolism, and cellular regeneration.
Bone Density and Muscle Growth:
MK-677 enhances bone formation by increasing osteoblast activity through IGF-1-mediated PI3K/Akt/mTOR signaling. IGF-1 stimulates osteoblast proliferation, improving bone mineral density and reducing fracture risk. It also upregulates mTOR, promoting protein synthesis and muscle cell growth, leading to increased muscle fiber size and improved muscle recovery.
Metabolic Regulation:
MK-677 increases basal metabolic rate (BMR) by enhancing lipid oxidation through AMP-activated protein kinase (AMPK) activation, promoting fat breakdown for energy production. It improves insulin sensitivity by modulating GLUT4 expression, facilitating glucose uptake in skeletal muscle, while also reducing systemic inflammation to support metabolic homeostasis.
Sleep Enhancement:
MK-677 influences GABAergic pathways in the hypothalamus, increasing GABA release, which enhances deep sleep (slow-wave sleep) and REM sleep phases. This improves growth hormone pulsatility, optimizing muscle repair, cognitive function, and overall recovery.
Consider Stacking With
- Any GHRH (CJC-1295, MOD-GRF-1295, Tesamorelin)
- BPC-157
- TB-4
- Semaglutide/Tirzepatide
- AOD-9604
- PEG-MGF
- 5-Amino-1MQ
- Kisspeptin-10
Side Effects & Cautions
Common Side Effects
- Injection site redness/itchiness/swelling (as reported)
- Joint pain and stiffness
- Edema
- Increased cortisol
Cautions
- Limit to 8–12 weeks to avoid receptor desensitization/internalization
- May cause irreversible neurological damage (reported)
Research & References
Research Highlights
Muscle and Bone Health: Increased lean body mass and improved bone density in elderly subjects.
Sleep and Cognition: Enhanced sleep quality with significant increases in REM and slow-wave sleep phases.
Fat Loss and Metabolic Support: Significant reductions in visceral fat and improved metabolic markers.
References
Bach, M. A., et al. "Effects of MK-0677 on Hip Fracture Recovery in Elderly Patients." J Am Geriatr Soc., 2004
Liu, X., et al. "Muscle Regeneration and Bone Health with MK-677 Treatment." Front Physiol., 2019
The Journal of Clinical Endocrinology & Metabolism. "Metabolic Effects of Long-Term MK-677 Use in Obese Adults." JCEM, 2017
Yen, S., et al. "Sleep and Cognitive Benefits of MK-677 in Older Adults." Neuroendocrinology Journal, 2015